Stick a piece of felt between the hammers and the strings to damper the attack. Use some light compression to bring the volume back in the mix. EQ to taste.

The reason why I didn't allow it in GD is because I had done with other tracks in the past. A user copyrighted the video on YT of them playing it to my track, it took ownership of the track which in turn gave me a copyright claim on my own music. It then put adverts on my music to make that person money.